ST_RemovePoint() - XY
:memory: #use in-memory database
SELECT AsText(RemovePoint(GeomFromText('LINESTRING(0 0, 1 0, 1 1)'), 1))
1 # rows (not including the header row)
1 # columns
AsText(RemovePoint(GeomFromText('LINESTRING(0 0, 1 0, 1 1)'), 1))
LINESTRING(0 0, 1 1)